Roller-bit.



H. A. BARDEEN..

ROLLER BIT.

APPLICATION FILED SEPT. I| 1915.

Lfm, PaIenIeaAug. 28,1917.

,- their action is a grinding one,

HUGH A. BARDEEN, 0F LOS ANGELES, CALIFORNIA.

ROLLER-BIT.

Specification of Letters Patent.

Patented Aug., 28, fllt?.

Application filed September 1, 1915. Serial No. 48,549.

To all whom t may concern Be it known that l, HUGH A. BARDEEN, a citizenof the United States, residing at Los Angeles, in the county of LosAngeles and State of California, have invented a new and usefulimprovement in RollenBits, of which the following is a specification.

My invention relates to the art of drilling oil wells or the like, thatsystem of drilling commonly designated the rotary system, in which along column or string of drill pipe is rotated by means of a tablelocated at the surface of the ground, the string of drill pipe carryingat its lower end some sort of a cutting tool commonly designated as abit The first object of the invention is to provide a bit which willrapidly and economically cut away the bottom of the hole especially whenworking in very hard rock.`

In the rotary system of drilling, a heavy mud is employed, this, mudbeing forced downwardly through the string of drill pipe and emergingthrough holes placed at or near the cutting portion of the hit. This mudis used for the purpose of carrying away the cuttings of the bit andalso for the purpose of providing hydrostatic pressure and cementingmeans for retaining the walls of the well.

It is common practice in the drilling art to employ a bit commonlydesignated as a fish tail bit, this bit consisting of a dat body havinga cutting edge at its lower end, such bits having special efficiency inthat the fiat body tends to thoroughly mix the mud and to compact it andforce it against the wall of the well. The flat body is also very ecientin guidin the cutting edges so that a straight hole will be roduced. Thefish tail bits are objectionab e, however, in that and they do not workwell in layers of hard rock, commonly termed shells The second object ofmy invention is to provide a bit which will have a fiat body adapted toguide the cutting members and y to thoroughly mix the mud, and which atthe same time will be provided with very eiicient cutting members,enablin it to drill much more rapidly than the iis tail bit. xthere havebeen produced in the ast, and are new on the market, a consideralenumber of bits in lwhich rolling cutters are employed. These bits arequite efficient, but are costly to maintain due to the special form ofand particularly to cutters employed and due to the fact that expensiveoiling devices have to be provided for the purpose of preventing wear onthe cutting members.

The third object of my invention is to provide a bit having a rotarycutting member which will be inexpensive to produce and replace andwhich will not require any special means of lubrication.

It has generally been assumed in the case of rolling cutters, that theyshould be designed in such a manner that there would be no rubbingaction of the cutters on the bottom of the hole. The majority ofinventors who have attempted to produce roller bits, have attempted touse conical rollers so that the speed of travel on all parts of theroller would correspond to the movement of the bit at that point on thebottom of the well. lt is my present opinion that this theory isincorrect and that the cutters of the roller bit should be so designedthat there is con siderable rubbing action. It is true that this tendsto wear the cutters, but it also tends to givethe bit a greater drillingcapacity which is highly desirable.

The fourth object of the invention is to provide a bit in which thecutters not only roll on the bottom of the hole, but in which certainparts of the cutters have an abrasive or cutting action tending togreatly increase the eiiiciency of the bit.

I have found that the most economical way to operate a roller bit is toprovide a bit which will have relatively inexpensive cutters which cutrapidly, thereby giving a bit of great capacity and which at the sametime can be quickly and easily replaced at nominal cost. i

The fifth object of the invention is to provide means for so securingthe cutters of a. roller bit that they can be readily removed andreplaced.

I have also found that any oiling system is expensive and troublesome,and the sixth object of the invention is to provide a bit which willoperate without the necessity for any such special oiling device.

lf have further found that there is a great tendency for fish tail bits,or similar bits, having a Hat body, to wear on their outer edges so thatthe usefulness of such body 1s greatly reduced after it has been in thewell for a short time.

Further objects and advantages will -be evident to one skilled in theart after an im specti'on of the attachedv drawing and a perusal of thefollowing specification.

In the drawing, which is for illustrative 'purposes only:

Fig. 2 is an enlarged section of a portion of the lower end of the bitwith one of the cutters in place thereon.

Fig. 3 isa partial section on the line ac3-m3 of Fig. 1 looking in thedirection of the arrows.

In thedrawing, 11 is the lower end of a tool joint or coupling securedto the lower end of the drilling string, the coupling 11 being threadedat 12 to receive a threaded projection 13 formed on the upper end of thebody 14 of the'roller bit. The side walls of the well are shown at 15,and the bottom lof the well is shown at 16. The body 14 is of elongatedform, as shown, and of slightly smaller diameter than the desired boreof the well. Secured at either'edge the'reof is a removable stripj17which is dove-tailed into the body 14 of the bit. A drilled hole 18connects a pair of drilled holes 19 and 20 which extend upwardly from4the lower edges 21and 22 of the body 14 and come municate with a centralhole 23 in the projection 12, which in turn registers with and connectsto an open hole 24 in the coupling 11, which is in open communicationwith the interiorof the string of drilling pipe. Secured to the lowerend of the body 14 is a projection 25, slightly wider than the bodyhaving two cylindrical pins 26 formed on either side thereof.

The pins 26 are machined to form smoothl clinders and the body of thebit is mac ined at right angles to the axis of the pins to formshoulders 27. Each of the pins 26 has an opening 28 drilled therein, theouter end of the opening bein threaded as shown at 29, and the inner enbeing smooth and of a somewhat smaller diameter than the threadedportion 29. Threaded in the openings 28 are cap bolts 30. Each of thesebolts has a head 31, somewhat larger in diameter than the pins 26, athreaded portion 32, fitting tightly in the threaded` portion 29 of theopening 28, a portion 33 of smaller diameter than the portion 32 andhaving a locking oove 34 out therein, and a small end 35 w ich projectsslightly through the projection 25 and ts into a small hole in an innerWasher 36. The inner washers 36 are placed on the pins 26 and are lockedin place not only by the end 35 but also by the clamping action of astationary bushing 37 which is held in place by the clamping action ofthe cap bolts 30. An outer Washer 38 is etter illustrate the method, of

and the method of attaching the placed between each of the heads 31 andthe stationary bushings 37. The washer 36, the bushing 37, and thewasher 38 form a removable stationary bearing surface for the cutters 40and 41, loose bushings 42 turning freely in the borey of the cuttersupon the bushings 37. Pins 43 are driven through holes formed in theprojection 25 engaging the grooves 34 and locking the cap bolts 30firmly in place.

rlhe pins 26 are inclined as shown in the drawing, with the horizontal,the outer cutter 41 bearing on a conical surface 50 adjacent to thewalls of the hole 15, and the inner cutter 40 lbearing on an inner cone51 .having its apex at the center of the hole. As the bit is rotated thecutter 40 continually rolls upon and cuts the cone 51, and the cutter 41continually rolls upon and cuts the cone 50.

The method of operation is'as Jfollows:

' The drill pipe Vbeing rotated by any of the standard methods, and mudbeing forced downwardly therethrough, this mud passes through the holes19 and 20, being forced downwardly over the cutters 40 and41, thesecutters rolling upon the bottom of the hole and cutting the cones 50'and 51 as previously described. The cutters in their preferred form havea screw thread cut on the periphery thereof. The cutters wear relativelyrapidly, but being of simple form they are cheap to produce and can bereplaced at a very small expense. 1f desired transverse cuts can be madeacross the face of the cutteirs 40 and 41 to produce a serrated cuttinge e. i

find in practice that one set of bushings will outlast several sets ofcutters. The pins 26 and 27 do not wear at all, being protected bybushings 37, and the washers 36 and 38 are readily replaced, thesewashers, however, wearing comparatively slowly. The long bod 14 steadiesthe bit in the hole, thorough y mixes' the mud, and greatly assists indiggin through the relatively soft formations. Iglo `dove-tailed edges17 are readily replaced as they become worn, so that the body 0 pensiveportion, can be operated indefinitely, the wearing parts all beingreplaceable.

The inclination of the cutters is very important, as it is practicallyimpossible to placev a cylindrical cutter in a well unless it is soinclined, due to the' diliiculty of reaching the outer edge of ithe holewith a cylindrical cutter. A cylindrical cutter can not be laced in'avertical hole, with its axis at an angle of approximatelyr25 lt claim asmy invention:

l. A roller bit for use .in an oil well comprising a body, an outer pinand' an inner' pin secured in said body at an inclination to the axis ofthe well, an outer cutter on said outer pin, and an inner cutter on saidinner pin, said pins being so located that Ieaid outer cutter rolls on apath around the outer portion of the bottom of the well, and said innercutter rolls on a path inside of the path of said outer cuttercomprising approximately all of the remainder of the bottom or" thewell.

'2. A roller bit for use in an oil well comprising a body, an outer pinand an inner pin secured in said body at an inclination to the axis ofthe well and approximately pan allel With each other, an outer cutter onsaid outer pin, and an inner cutter on said inner pin, said pins beingso located that said outer cutter rolls on a path around the outerportion of the bottom of the well, and Said inner cutter rolls on a pathinside of the path of said outer cutter comprising approximately all ofthe remainder of the bottom of the Well.

3. A roller bit for use in an oil well eemprising a body, an outer pinand an inner pin secured in said body at au inclination to the axis ofthe well, a cylindrical outer cutter ou said outer pin, and acylindrical inner eutter on said inner pin, Said pins being S0 locatedthat said outer cutter rolls on a path around the outell portion ol thebottom of the well, and said inner cutter rolls on a path inside of thepath of said outer cutter comprising approximately all of the remainderof the bottom of the well.

if. A roller bit for use in an oil well coinprisinga body, an outer pinand an inner pin secured in said body at au inclination to the axis ofthe well and approximately parallel with each other, a cylindrical outereutter on said outer pin, and a cylindrical inner cutter ou said innerpin, said pins being so located that said outer cutter rolle on a patharound the outer portion of the bottoni of the well, and said innercutter rolls on a path inside ol the path of said outer cuttercomprising approximately all ot the remainder of the bottom of the well.

ln testin'iony whereof, l here hereunto set my hand at Los Angeles,California, this 27th day of August, 1915.

HUGH A. BARDFICN.

